The present invention relates to robotic apparatus and, more particularly, to gripper apparatus having fingers that are driven by rotary actuators.
Gripper apparatus are used in the robotic field for moving workpieces, or the like, from one position to another. Also, gripper fingers may be used to perform different operations on a workpiece. Generally, the fingers of the gripper apparatus are pneumatically or hydraulically activated for grasping and releasing workpieces.
The current art is shown by U.S. Pat. Nos. 4,577,898 and 4,607,873, both issued to Nusbaumer, et al. The fingers of these apparatus are activated by reciprocating piston actuators. A disadvantage of this type of apparatus is that the up and down reciprocating movement of the piston must be translated into side to side lateral movement of the fingers. This translation of movement is accomplished by a linkage bar device which must be precisely set in order for the fingers to move through their proper stroke. Also, the working surface of the piston is limited to the diameter of the piston cylinder. Further, these types of apparatus do not have a means for locking the fingers in position if a power failure occurs. Thus, if a pneumatic or hydraulic hose breaks on the apparatus and the workpiece is in an elevated position, the workpiece will be released with significant potential negative effects.
The present invention overcomes the disadvantages of the above art by providing the art with a gripper apparatus having a rotary actuator. The present invention enables the gripper apparatus to lock during movement of the gripper fingers if power to the actuator is lost. The present invention also enables sensing of the gripper fingers while they move fron one position to another.
The present invention provides the art with a new and improved gripper apparatus. The gripper apparatus of the present invention includes a body, fingers for grasping and releasing a workpiece are supported by the body, a pair of yoke members supported by the body for providing the fingers with straight line movement, and a cam mechanism associated with the yoke members for driving each of the yoke members in a reciprocating linear motion. A rotary actuator is associated with the cam mechanism to rotatably drive the cam mechanism which, in turn, translates the rotary movement of the rotary actuator into reciprocating linear movement of the yoke members to drive the fingers away from and towards one another along a linear path.
The present invention may also include a lock mechanism associated with the cam mechanism and rotary actuator. The lock mechanism enables the fingers to be locked at any position along the reciprocating linear stroke of the fingers. This lock mechanism enables a workpiece to be locked in position if power to the actuator is lost.
The present invention also may include proximity switches mounted on the body. The proximity switches sense the reciprocating linear movement of each yoke member. The proximity switches may communicate with a microprocessor for enabling control of the gripper apparatus to perform different functions.
From the subsequent description and the appended claims taken in conjunction with the accompanying drawings, other objects and advantages of the present invention will become apparent to one skilled in the art.